Gang-saw.



J. W. BELL.

GANG SAW.

APPLICATION FILED JAN.19,.1909. 931,912. Patented Aug. 24,1909.

. 2* 3 WITNESSES: M John Wmran 5e22,.

ANDREW B, (mum cm nnmmuoowmmzs. wAsumsrca. D. c.

ATTORNEY.

-UNITED STATES PATENT FFTCE.

JOHN WARREN BELL, OF VANCOUVER, BRITISH COLUMBIA, CANADA.

GANG-SAW.

To all whom it may concern:

Be it known that 1, JOHN l/V. BELL, a citizen of the Dominion of Canada,resioling at Vancouver, in the Province of British Columbia, Canada,have invented new and useful Improvements in Gang- Saws, of which thefollowing is a specification.

This invention relates to the manner of mounting the frame or gate of agang or muley saw such as is used for cutting up logs into boards, andmy improvement is directed to the suspension of the slides in which thesaw frame is vertically reciprocated whereby the saw frame at the upperend of its stroke recedes from the log feed in a manner to avoid the logadvancing against the saws while they are traveling at a slow rate ofspeed as the crank passes over the upper quarter of its movement.

In gang saws of this class the frame of saws is withdrawn from thecutting face during the upstroke to clear the saws from the cut andpermit the sawdust to fall clear. The saw frame is usually verticallyreciprocated by a crank and while the crank pin is passing around theupper quarter of its movement the saws are moving slowly while the logis advancing and a heavy strain is thus imposed upon the saws. Where thesaw is for small logs this fault may be avoided by an intermittent feedof the log but in large logs it is obviously inconvenient to have anintermittent feed and it is therefore desirable to provide some meanswhereby the saw frame will recede'before' the advance of the log duringthat portion of the downward movement of the saw frame while the crankpin is passing over the upper quarter of itscircle. It is to efiect thisobject that the invention which is the subject of this application hasbeen devised.

The invention is particularly described in the following specification,reference being made to-the drawings by which it is accompanied, inwhich Figure 1 is an elevation of a portion of a gang saw frame showingits connection to the main frame of the machine, and Fig. 2 a crosssection on the line A A in Fig. 1 showing the manner of suspending andoperating the slides in which the gang frame vertically moves.

The various parts of the mechanism by which the saw frame is withdrawnfrom and advanced toward the cutting face on the log are practically thesame as at pres- Specification of Letters Patent.

Application filed January 19, 1909.

Serial No. 4-73, 125.

gang saws for heavy secured is vertically reciprocated in slides r 8 bya crank 4 from a crank shaft 5. The slides 8 are suspended at theirupper ends from the main frame 10 of the machine and their lower endsmoved to and from the approaching log as required by a mechanism to bedescribed.

The saw frame 2 is provided with slide blocks 6 at the top and bottom ofeach side which slide blocks arepivotally mounted on pins 7 projectingfrom the sides of the saw frame that the frame may retain its verticalposition during the moving of the slides. The lower ends of the slidesare moved to and from the face of the cut by an eccentric 15 on thecrank shaft 5 which eccentric is connected by a rod 17 to a lever 16secured on an upper rocker shaft 13 on which is secured at each side abell crank 12 one arm of which is connected by a link rod 11 to thelower end of each upper swinging slide 8. The other arm of the bellcrank 12 is connected by a link rod 14 to;a corresponding bell crank onthe lower rocker shaft 13 by which the same movement is imparted to thelower swinging slides. The eccentric 15 is set at somewhat over ninetydegrees in advance of the crank so that when the crank is at the upperend of its movement the lower ends of the slides 8 will be in theposition shown in the drawing that is moving toward the face of the log.This however is not material to the principle of the invention althoughit is conducive to its more correct working, the essential feature ofthe invention lying in the location of the pin 9 on which the slides aresuspended, at a position below the center 7 of the slide blocks whenthey are at the upper limit of their movement. The object of which isthat when the lower end of each slide is moved towards the cutting faceof the log in the direction of the arrow shown, the upper end, where theslide blocks of the saw frame are, is receding from the log, so whilethe saws are moving slowly at the upper end of the stroke the frame willmove back before the advance of the log until in its descent the slideblocks 6 pass the point of suspension 9 of the guides when they willadvance toward the cut in the desired mani 1 ner.

The eccentric rod 17 is connected to the Patented Aug. 24, 1909.

rocker arm 16 by means of a die 18 in an elongated slot 19 so that theamount of ad vance and recession of the saw frame may be regulated tothe rate of feed of the logs. This adjustment may be effected by a screwand hand wheel as drawn but will preferably be cooperative with themechanism by which the feed of the log is regulated so that in varyingone the other will be correspondingly varied. This cooperative mechanismis not shown in the drawing as it is not material to the invention,which consists essentially in the location of the point of suspension ofthe guides 6 in the manner before described. The distance of this pointof suspension from the center of the guide blocks when they are at theupper end of their movement should be approximately the versed sine 20of the arc of the upper quarter of the movement of the crank pin asshown in the lower part of Fig. 2. With this proportion the downwardline of movement of the saws in relation to an advancing log ispractically a straight line. With this movement properly adjusted thereis no lost motion but as soon as the frame commences its downwardmovement the saws meet their cut with a feed properly proportioned tothe speed of descent.

The improvement is one that involves no extra expense as it consistsmerely in the altered position of the point of suspension of the slides.

Having now particularly described my invention I hereby declare thatwhat I claim as new and desire to be protected in by Letters Patent is:

1. In a gang saw having a saw carrying frame that is verticallyreciprocated by a crank, means for withdrawing the saw frame from theface of the cut on a log during the early part of the downward stroke ofthe saw frame, and for thereafter advancing it toward the out whilemaintaining said saw frame with the saws constantly in a vertical planeat right angles to the line of travel of the log.

2. In a gang saw having a saw carrying frame that is verticallyreciprocated by a crank, means for withdrawing the saw frame from theface of the cut on a. log during the early part of the downward strokemeans of a crank, means for withdrawing the saw frame from the face ofthe cut during the downstroke of the saw frame and advancing it theretoduring the latter part of the stroke while maintaining the saw frame andthe saws always in vertical planes and at right angles to the line oftravel of a log, said means comprising, slides in which the saw framevertically moves said slides suspended from the frame of the machine ata point below the upper end of the movement of the saw frame in theguides, and means for moving the lower ends of the guides toward the cuton the log during the downstroke and for withdrawing them therefromduring the upstroke.

4. In a gang saw having a saw carrying frame, a pair of upper and lowerslides in which said jaw frame is vertically reciprocable, means joiningsaid upper and lower slides to be moved in unison, means for pivotingsaid upper and lower slides to the machine frame, and means cooperatingwith said joining means for moving said slides on their pivots at timesto withdraw the saw frame from the face of the cut on a log'during theearly part of the down stroke of the saw frame and for thereafteradvancing it toward the out while maintaining the saw frame with thesaws constantly in vertical planes and at right angles to the line ofmovement of the log.

In testimony whereof I have signed my name to this specification inthepresence of two subscribing witnesses.

JOHN WARREN BELL.

l/Vitnesses I A. Gr. IVOOLSEY, ROWLAND BRITTAIN.

